The system and method of this invention relates to an implantable spinal fixation system for the surgical treatment of spinal disorders and apparatus for implantation.
Spinal column disorders such as scoliosis, kyphosis, lordosis, spondylolisthesis, ruptured, broken, fractured or slipped discs are treated with spinal fixation. Spinal fixation uses surgical implants or constructs which mechanically immobilize the treated area of the spine with the goal of causing the fusion of the treated vertebrae. One type of spinal fixation utilizes a pair of longitudinal rods that run parallel or longitudinally along the spine and are affixed to pedicles of the appropriate vertebrae or to the sacrum and act as anchor points for the longitudinal rods. Bone screws are generally placed two per vertebrae with one at each pedicle on either side of the spinous process of the vertebrae. Clamp assemblies join the spine rods to the screws. When a pair of transverse rod/connectors are fastended in parallel on either side of the spinous process, the assembly can be significantly strengthened. However, the instrumentation with transverse rods described requires open surgery and a large incision. In doing so, the skin and tissue surrounding the surgical site must be cut, removed and or repositioned in order for the surgeon to access the location where the stabilization device is to be installed. This type of invasive surgery leads to risk of long recovery time, disruption of muscle, trauma damage and scarring to the tissue.
In recent years minimally invasive spinal (MIS) procedures have become more common. The advantages of MIS procedures compared with open surgery are less pain, faster recovery, less intra-operative blood loss, and generally greater patient satisfaction. With the advent of innovative devices and techniques, physicians now routinely perform MIS procedures that traditionally would require open surgery. One of the shortcomings of MIS procedure/surgery is the inability to place a transverse connector through a percutaneous route. Transverse connectors are used during spinal instrumentation procedures to add rigidity to the overall construct offered by longitudinal rods alone. Transverse rods add stability during axial rotation (twisting) and lateral bending (side to side bending) of the spine. During open procedures the placement of transverse connectors are straight forward but require muscle dissection as well as other downsides mentioned herein.
Minimally invasive surgery wherein a long incision through a muscle group such as those along the spine to expose multiple levels of vertebrae is not required. Minimally invasive surgery may be achieved with percutaneous minimally invasive spinal procedures where minimal if any muscle dissection is required. Currently minimally invasive surgery is not available to insert transverse rods into the spine, for example, to add rigidity to an instrumentation construct consisting of pedicle screws and longitudinal rods involving multiple levels of vertebrae.